Saad Haj Bakry, PhD, CEng, FIEE 1 Performance Evaluations Saad Haj Bakry, PhD, CEng, FIEE P RESENTATIONS IN N ETWORK M ANAGEMENT

Saad Haj Bakry, PhD, CEng, FIEE 2 Objectives / Contents Service Measures Delay: Store & Forward Congestion: Circuit Switching Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 3 Service Measures Faults Information: Loss Security Compression Quantitative / Qualitative Congestion Delay Processing Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 4 Measures: Q & Q MeasuresDescription Performance Technology Capabilities. User Satisfaction Natural Feel Quantitative Parameters Clearly Defined (Mathematically) Evaluated Numerically Qualitative Parameters Like and Dislike. Ease of Use. Social and Behavioural Factors. Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 5 Measures: Faults (1/3) MeasureDescription MTBFMean Time Between Failures MTTRMean Time to Repair Availability (should be 99%) The proportion of time when the system is available for use Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 6 Measures: Faults (2/3) Frequency distribution of 100 mixed faults associated with 4 types ( Measure of “ Strengths & Weaknesses” of Components) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 7 Measures: Faults (3/3) WeaknessDescription Logical DeficiencyLack of resources to performing the operations correctly. e.g. Message Reassembly Space in Virtual Circuit Operations Protocol Un-Robustness Lack of “built-in” “fault-tolerant” capability to deal with components failures and stress conditions e.g. Routing Problem : Circulation of Packets. Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 8 Measures: Congestion MeasureDescription NOSNumber of Successful Attempts NOFNumber of Failed Attempts Congestion Service Levels Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 9 Measures: Delay MeasureDescription Elements (Point-to-Point) Processing /Queuing / Transmission / Propagation. End-to-End Source to Destination Delay (from Sending to Receiving) Jitter Deviation from Average Synchronization Audio-Video “Lip Synchronization” Delay Sensitivity Audio & Video (Online) Streams Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 10 Measures: Processing MeasureDescription [i]Instruction type index T[i]Processing time of instruction [i] F[i]Relative frequency of instruction [i] in the application considered TAverage processing time per instruction Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 11 MeasureDescription Loss of Information Signal-to- Noise Ratio. Signal-to-Interference Ratio. BER: Bit Error Rate. Cell-Loss Rate Jamming: Loss of Communications Loss Sensitivity Data (Text) Streams. Measures: Information ( Loss) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 12 MeasureDescription IntegrityInformation: Loss Destruction Modification Confidentiality Unauthorized “Disclosure” of Information: “Encryption / Attack” Blocking “Denial” of Service Measures: Information ( Security) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 13 Measures: Information ( Compression) MeasureDescription Video PCM (BW: 4.2 MHz).(Sampling: 2). (Sample:16 bits) = 135 Mbps [Compressed to 45 Mbps] Digital Video (Pixel: 24 bits).(SVGA: 800 x 600 pixels). (Frames: 25 per sec) = 288 Mbps Compression TV Quality = Mbps Cable TV Quality = Mbps Low Rate Videoconferencing = 384 kbps – 1.5 Mbps “Ratio”Ratio = Encoded Size / Compressed Size Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 14 P RINCIPLES E RLANG- B F ORMULA O PERATION T RAFFIC Congestion: Circuit Switching Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 15 O BJECTIVE: Enabling Sub channels to be Assigned to Users “ Dynamically ” on Demand (Not on Fixed Basis) U SE: Suitable for Burst / Random Use C ONCEPT: Sub channels Assigned on Demand for Active Use and Released when Activity is Completed Principles (1/2) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 16 TDM / FDM C IRCUIT S WITCHING USERSUSERS Users Generating Demands Dynamic Assignment / Release on Demand “ N ” Sub Channels Channel Sharing Shared Channel Principles (2/2) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE D IAL- U P 3. C ALL P ROGRESS 4. C ALL T ERMINATION 2. S IGNALLING / R OUTING / A SSIGNMENT 5. R ELEASE Operations Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 18 T WO R ANDOM P ROCESSES C ALL A RRIVALS: Random Distribution (Poisson Process) C ALL D URATION: Random Distribution (Negative Exponential Distribution / Related to Poisson Process) Traffic (1/3) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 19 R [Calls / Time Unit]: Rate of Generated Calls D [Time Unit]: Average Call Duration A [Erlang]: A = R.D B USY H OUR P RINCIPLE E RLANG: “ 1 ” Erlang is Full Channel Occupancy For “ 1 ” Time Unit Traffic (1/3) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 20 “ 1 ” E RLANG R = 1 [Calls / Hour] D = 60 [Minutes] A = 1 [Erlang] R = 4 [Calls / Hour] D = 15 [Minutes] A = 1 [Erlang] R = 12 [Calls / Hour] D = 5 [Minutes] A = 1 [Erlang] Traffic (3/3) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 21 T YPICAL / S IMPLE C ASE S TUDY S YSTEM: “ N ” (Sub) Channels Fully Available to All Call D EMANDS / T RAFFIC O FFERED BY ALL U SERS : “ A ” [Erlang] P ERFORMANCE / G RADE OF S ERVICE / B LOCKING P ROBABILITY “ B ” Erlang “B” Formula (1/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 22 B = (A N / N!) / (A i / i!) B = 1 / (N! / (A i (N - i)!)) Erlang “B” Formula (2/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 23 O THER I MPORTANT F ACTORS T RAFFIC C ARRIED / S ERVICED: K = A (1 - B) A VERAGE C HANNEL U TILIZATION / O CCUPANCY: Q = K / N Erlang “B” Formula (3/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 24 P OSSIBLE U SE S YSTEM E VALUATION: Given: N / A Find: B / K / Q S YSTEM C APACITY: Given: N / B Find: A / K / Q S YSTEM D ESIGN: Given: A / B / K Find: N / Q Erlang “B” Formula (4/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 25 P RINCIPLES O PERATION T RAFFIC D ELAY A NALYSIS M ESSAGES: Packets Frames Cells (Switching / Relay) Delay: Store & Forward Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE I 2 N IIII P MM S HARED C HANNEL B UFFER P ROCESSOR S TORE & F ORWARD c c c [bps] c C [bps] Dynamic Channel Assignment (Active Users Only) / Efficiency USERS > N Where N = C/c Principles (1/2) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 27 B URST U SE U SE L OSS S ENSITIVE I NFORMATION: “ D ATA / T EXT ” N O D ELAY S ENSITIVE I NFORMATION: “ V OICE / P ICTURE ” ; E XCEPT IN H IGH S PEED Principles (2/2) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 28 M ESSAGE: An Information Signal Sent by a Single User Physical Block (Basic Name: for M / P / F / C) P ROBLEM: Fluctuating Size Need for Size Control “ P / F / C ” (Logical Units) Providing Better Sharing Messages (1/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 29 P ACKET: X.25 / 64 kbps Variable Size H: 8 bytes F RAME: T-1 / E-1 Variable Size H: 2 bytes I NFORMATION H EADER H EADER: S OURCE / D ESTINATION / C ONTROL I NFORMATION: C ONTROLLED S IZE C ELL / ATM : OC-3 / OC-12 Fixed: 48 Bytes H: 5 bytes Messages (2/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 30 D ATAGRAM : Logical Units (Packets) are Routed Independently Through the Network from Source to Destination V IRTUAL C IRCUIT: Physical Units (Messages) Sent from Source to Destination Look as if they Passed Through a Circuit Example: DATAGRAM with the Packets of a Message Reassembled at Destination Messages (3/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 31 P ACKET: Point-to- Point & End-to- End F RAME: End-to-End Only E RROR C ONTROL C ELL / ATM : End-to-End (Header Only) L OW N OISE: Eases Error Control Protocols. H IGHER S PEED: Reduces Delay and Helps Information Integration (Data / Voice / Picture) Messages (4/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 32 P MM M [bits] N EXT N ODE D ELAY E LEMENTS P ROCESSING D ELAY “ p ” Q UEUING D ELAY “ q ” T RANSMISSION D ELAY “ s ” P ROPAGATION D ELAY “ g ” pq sg M ESSAGE D ELAY: d = p + q + s + g C [bps] l [km] v [km/s] / Sec. Operation (1/3) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 33 P ROCESSING D ELAY: Dependent on Processing Independent of Traffic Q UEUING D ELAY: Dependent on Traffic (Drive) / Capacity (System) Analysis Required T RANSMISSION D ELAY: s = M / C Dependent on Message / Capacity (System) Independent of Traffic Volume / Fluctuation P ROPAGATION D ELAY: g = l / v Dependent on Channel / Distance (Geography) Independent of Traffic / Capacity Operation (2/3) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 34 P ROCESSING D ELAY: Significant in High Speed Links Q UEUING D ELAY: An Essential Element, as it is Associated with the Capacity / “ System ”, and Traffic Volume / Fluctuation / “ Demands ” T RANSMISSION D ELAY: An Essential Element, as it is Associated with the Capacity / “ System ”, and the Message Length / “ Demands ” P ROPAGATION D ELAY: Significant in Satellites g = 36 / 300 = 0.12 sec Operation (3/3) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 35 T WO R ANDOM P ROCESSES M ESSAGE A RRIVALS : Poisson Process M ESSAGE L ENGTH: Negative Exponential Distribution / Fixed Size Messages (Deterministic) Traffic (1/2) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 36 R [Messages / Sec]: Rate of Generated Messages M [Bits] : Average / Fixed Message Length B USY H OUR P RINCIPLE T RAFFIC R ATE: A [bps] = R. M Traffic (2/2) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 37 Q UEUING D ELAY: Variable Message Length q v = (RM / C) / ( (C/M) - R) Fixed Message Length q f = (1/2). qv Delay Analysis (1/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 38 E SSENTIAL D ELAY E LEMENTS: d = q v + s = 1 / ( (C/M) - R) L IMITATION: RM < C U TILIZATION / O CCUPANCY: U = (RM) / C Delay Analysis (2/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 39 D: N ORMALIZED D ELAY: ( M ESSAGE T RANSMISSION TIME “ s ” ) IN T ERMS OF U TILIZATION “ U ” : D = d / s = 1 / (1 - U) D [Unit-less] : Number of Messages in the System (queued & transmitted) Delay Analysis (3/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 40 P OSSIBLE U SE S YSTEM E VALUATION: Given: C / M / R Find: d / U / D S YSTEM C APACITY: Given: C / U (d/D) / M Find: R S YSTEM D ESIGN: Given : R / M / U Find : C Delay Analysis (4/4) Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 41 P ERRFORMANCE C OMPUTATIONS: Congestion / Delay Conclusions P ERRFORMANCE U DERSTANDING: Q&Q / Faults / Congestion / Delay / Processing / Information P ERRFORMANCE M ONITORING / M ANAGEMENT Performance Evaluations

Saad Haj Bakry, PhD, CEng, FIEE 42 References Telecommunications Management: Operation & Management of Networks, National Computing Centre (NCC) Training, UK. David Etheridge and Errol Simon, Information Networks: Planning and Design, Prentice Hall, UK.  Gruber J.J., Transmission Performance Of Evolving Telecommunications Networks, Artech House, Boston-London, Performance Evaluations